The interaction of gonococci of varying colonial types, pilation, and state of virulence with human polymorphonuclear leukocytes, monocytes, and macrophages will be evaluated, and the effects of semen (including prostaglandins) and serum on this interaction will be studied. We will determine whether gonococci may persist within cultures of human macrophages as facultative intracellular parasites, the influence of lymphokines on macrophage handling of the gonococcus, and the ability of macrophages to protect gonococci from extracellular antimicrobial agents.